How do you unsync apps?

I synced my touch with my old hdd and when I got the new hdd, I neglected to copy over all of my apps from the appstore. Is there anyway that I can unsync the ipod so I can put new apps on it, preferably without having to delete all of the apps currently on it?

Let's just say that I haven't taken the LEGAL way to get apps. And having to delete them is terribly inconvenient.

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then if they weren't legal apps then iTunes cant recognize those apps as they are not directly from the app store. so in theory they shouldnt be deleted. just the ones that you got from the app store would get deleted.